A better premise would have been...

Kevin purposely boards the wrong plane to New York to have his way.

This makes him the villain.

You basically don't see him because they are searching for him. The focus of the story is the other children who use their detective skills to search for Kevin. Buzz leads this search.

As a strange twist, they hire the wet bandits to also search, promising them they'll give them 5 minutes alone with the boy to inflict all the injuries they suffered.

But while in New York, they discover that Kevin went to New York to visit Old Man Marley, who had ended up in a hospice. He isn't missing, he's been kidnapped by the young sales clerk who let him run off with the toothbrush, a mistake that cost him his job. The pizza guy is his cousin and is also in on it.

Instead of the wet bandits wanting to hurt Kevin, they decide to use what he taught them to fight these two.